Looking for sound advice (optical audio)

**ff89** · 03-09-2010, 11:24 AM

Hello. I've been a long-time lurker on these forums and will be purchasing a new vehicle in the very near future. I have about 2-3 months to wait until the vehicle arrives at the dealer and am hoping to have my carpc and sound system bench-tested and ready to go by then.

That being said, I've been doing computers and networking many years as a hobby and am an electronics technician (component-level circuit card repair) by trade. I've built a number electronic and digital-logic projects in the past. The concept of a carpc merges these two fields of computer science and electrical engineering, and I'm quite excited at the prospect of building one.

Okay, now that I have the backstory out of the way, I have a few questions concerning my future setup. I'll start with one for now.

The vehicle I have on order is a 2010 Dodge Ram 1500 Regular Cab ST. I purposely turned down the upgraded sound system being that whatever comes factory installed will be swiftly removed. According the manufacturer's specifications, my vehicle comes with a stock 6-speaker setup (2 in the dash, 2 in the doors, and 2 behind the seats). I have a few ideas on how to tie this into the carpc setup, and I'd like to see what everyone recommends.

I'm considering two possible setups.

1) Install a 3-way component speaker system on each side of the truck in the stock speaker locations in addition to 2 12-inch or 10-inch subwoofers, depending on available space. The computer would see this as a 2-channel stereo configuration, and crossovers would send the correct frequencies to the correct component speakers.

2) The second option would be to install full-range speakers in the factory locations and run each one on its own channel, in essence making a 6.2 surround sound system. This would allow much louder audio (unless someone knows of a 3-way component system that handles over 100 watts/channel), but I'd lose the quality of a component system.

I'd very much like to use an SPDIF optical connection from the computer to the amplifier (mainly because of sound quality issues). Unfortunately for me, there are VERY few car audio amplifiers that support optical connections. My plan is to run optical from the computer to a sound processor near the amps, and a short RCA path cable from the sound processor to the amplifiers. What is everyone's recommendation for a simple optical-to-RCA sound processor/decoder? It would have to support 24-bit PCM.

If I chose to go with a 6 individual channels, the only way I know of to get the audio from the computer to the sound processor would be using a Dolby Digital Live sound card. Unfortunately, DDL only supports up to 5.1. Are there any sound processors that support Dolby Digital Decoding and can run virtual surround on the back two speakers (virtual 7.1)? Otherwise, my back two speakers might as well not be installed.

I suppose I could just scrap the optical idea and go analog all the way, but that still doesn't determine if I should go with 3-way components or 6 full-range speakers.

Any input is greatly appreciated; I'm really torn on this issue and hopefully some of the "been there, done that" guys can help me out!

By the way, if anyone has any electronics, soldering technique, or computer-specific questions, I'd be happy to help answer them.

Thanks!

**soundman98** · 03-09-2010, 02:33 PM

welcome to the forums!

specific sound qestions like this are always hard to answer, because so much of it is subjective..

so, i'll just go over the different options

a little preface: i am not a 'uber-audiophile' i like clean, loud music, but am not to picky about the bitrate of my digital media as long as it is above 128bps, and really cant tell a difference between a 16 bit audio stream and 24 bit stream...

for audio processing, you could use a audio program like audiomulch or console, and then send it out to the amps.

or you can just use a optical cable to a processor like the bitone.

for speakers, my 3 way active setup(2way+sub) is louder than most fullrange speakers-- because each speaker is getting only the frequencies that it can play easily, and there is no longer any passive crossovers sucking power away from the audio.

rear speakers are personal preferance, but i don't use them in my families ranger, and have disconnected them in my own car--i think that the closer the rear speakers are to your seat, the less you need them, and the more they hurt the imaging of the front speakers

**PhilG** · 03-09-2010, 02:55 PM

I cannot speak as a "been there done that guy". I can speak as a "going to be there soon guy".

Optical is a great way to go if you don't mind all of the harware required to do it. Otherwise a quality set of RCA and line drivers can get you there as well
My computer is still on the bench but has been tested only with RCA's to date so I am far from an authority but here is my setup:
Laptop>USB> X-Fi sound card>Optical out> Alpine PXA-H700 processor> tuned via
RUX C701 Alpine controller> RCA's> Infinity 600a + Infinity 7541a amps> sub + 2way components(front)+2 ways rears+ SBS-0715 Alpine Centre Channel w/it's own amp.

I have read your whole post and here is what jumps out at me:

3 ways may be overkill for your front stage, 2 way components would likely suffice. Tuning will be much easier as well.
Rear speakers don't need to be of insane quality, a nice set of 2 ways will work, they are just filler. Or don't even bother with rears. Most guys going for SQ don't even run them.

I'm not sure in a regular cab if the space is there to really enjoy true surround sound. I think I would focus more on the front stage with a good amp and go for straight SQ.

I would focus on 1 good 10" or 12" sub with enough amp and ensure it's a good piece and has enough air space to perform properly. 2 cheaper subs in too small of box will be disappointing.

Just my 2 cents, there are many way to go about this and they will all work. Remember, the sound quality has to impress only you when you are done to be an SQ setup!

**ff89** · 03-09-2010, 09:15 PM

Well, there's certainly a lot to think about. I like the idea of going with a nice 2-way component setup in the front and some full-range fillers in the back.

The issue with the is installation: Do I want to put the tweeters in the dash location and the mids in the doors? This seems like the imaging would be kind of odd having the mids so far below ear level. Although this is similar to the common setup of tweeters in the pillars and mids in the dash, just shifted down a few feet. I could put the mids in the dash and the tweeters elsewhere, but this seems like it wouldn't be quite as aesthetically pleasing, and this will be a brand-new truck... I'm not too keen on the idea of cutting into the plastic molding to mount tweeters when I have six factory locations available.

Likely I'll stick a good quality set of full-range 2-way or 3-way filler speakers in the back. As far as the subs, I'm open to going with a single 10" or 12", provided I can find a speaker with sufficient volume and good sound quality.

For the digital setup, I think I'll probably go with a sound processor linked to an X-fi card (big fan of the 24-bit Crystallizer) in the computer. Deciding which audio processor is a whole other issue.

As always, any input is more than welcome.

**kross** · 03-10-2010, 12:05 AM

Originally Posted by ff89

The second option would be to install full-range speakers in the factory locations and run each one on its own channel, in essence making a 6.2 surround sound system. This would allow much louder audio (unless someone knows of a 3-way component system that handles over 100 watts/channel), but I'd lose the quality of a component system.

I believe just about every quality component speaker set can handle over 100 watts.

I've been feeding my Rainbow Germaniums about 175 watts for about a year now, and they handle it fine. The Rainbow Powerlines can handle over 300 watts (actually well over 300, I know of one person giving his 400 watts per side), as can the Hertz Mille series (and probably many others, those are just the ones I'm familiar with).

**PhilG** · 03-10-2010, 07:06 AM

"This seems like the imaging would be kind of odd having the mids so far below ear level"

In my opinion, the mids being mounted low is not as big an issue is have them mounted off axis. If you can get them pointed up and towards the rear of the vehicle even a little bit, it will help alot.

"I'm open to going with a single 10" or 12", provided I can find a speaker with sufficient volume and good sound quality."

Believe me this one isn't my opinion, this one is fact -the right sub/amp/box combo will be capable of "rattling your teeth out"

and can sound good. For an SQ sub, look at Alpine Type R I am told. I bought an RD Sonance which I have yet to install but am told it is has excellent SQ so we will see.

**Gbus** · 03-10-2010, 07:29 AM

I would personally go with a 3-way setup in front and ignore the rears at first. Make that front stage as strong as you can and worry about the rear fill after plus those rear speakers are brand new and will do fine as rear fill IMO.

As kross said, Rainbows can handle over 100w and if you are looking into quality speakers they mostly all thrive over 100w power. Hertz is a fantastic audio company as well. But the brands/sound is subjective to the owner/listener. Majority of guys on my car forum use Infinity speakers and love them. I personally don't really like the sound. So you need to hear some choices. Anyway, the 3-way setup would be my choice as each speaker gets the frequencies it is designed to get and spit out so it should be clean and loud. I know that Image Dynamics 12" is a commonly used sub. It's raved about on some car audio forums I've been on. Take a look into that.

Btw, what amp/s are you going to run the speakers off?